#include <avr/io.h>
#include <util/delay.h>

int main()
{
	DDRB=0xff;
	PORTB=0;
	while(1){
		PORTB=0x00;
		_delay_ms(500);
		PORTB=0xff;
		_delay_ms(500);
	}
	return 0;
}	
